Technical Field
The present disclosure relates to an organic light-emitting display (OLED) device, and more particularly, to an OLED device capable of suppressing interference that may occur between a line and an organic light-emitting element while achieving high resolution and high definition by disposing a plurality of lines on different layers using a planarization layer so that they are insulated from one another.
Description of the Related Art
An organic light-emitting display (OLED) device includes an organic light-emitting element including an organic emitting layer, an anode and a cathode, and driving elements for driving the organic light-emitting element, such as a transistor, a capacitor, etc. In detail, an OLED device utilizes the phenomenon that holes injected from the anode and electrons injected from the cathode recombine in the emitting layer to form excitons, such that light of a particular wavelength is generated as an energy is released when the excitons relax from an excited state to the ground state.
An OLED device is capable of producing light in its own and thus does not require any additional light source, unlike a liquid-crystal display (LCD) device. Therefore, an OLED device can be made lighter and thinner than an LCD device. And, an OLED device has advantages in that it is driven with low voltage to consume less power, and that it has shorter response time, wider viewing angle and good contrast ratio (CR). For these reasons, an OLED device is currently under development as the next generation display device.
An OLED device includes a plurality of sub-pixels connected to a plurality of lines. Each of the plurality of sub-pixels includes a thin-film transistor, a capacitor, and an organic light-emitting element. The thin-film transistor and the capacitor may be connected to lines to transmit driving current to the organic light-emitting element based on the electrical signals on the lines.
Recently, as demand for a high-resolution OLED device has increased, researches have been made to densely dispose lines, thin-film transistors, capacitors, and organic light-emitting elements, etc. As the lines, the thin-film transistors, the capacitors and the organic light-emitting elements are densely disposed, the lines and the organic light-emitting elements may overlap with each other in some areas.
As the lines and the organic light-emitting elements overlap with one another, interference may be caused by signal applied to the lines in the organic light-emitting element. For example, parasitic capacitance may be formed between the anode of the organic light-emitting element of a sub-pixel and a data line. Such parasitic capacitance causes crosstalk between the anode and the data line and may result in interference on the voltage applied to the anode. As a result, the amount of the driving current flowing in the organic light-emitting element is changed, and accordingly ripples are generated, which may result in a change in the luminance of the organic light-emitting element.
As mentioned above, as an OLED device does not require any additional light source unlike an LCD device, the OLED device can be made lighter and thinner, and thus it is easier to fabricate a flexible OLED device. Accordingly, OLED devices can find a variety of applications in mobile phones, smart watches, laptop computers, tablet PCs, TVs, etc.
The flexible display device may include a curved display device, a bendable display device, a foldable display device, a rollable display device, etc. The flexible display device can reduce the width of the bezel to make viewers get immersed into the contents displayed on the screen. The width of the bezel can be reduced by bending or folding the non-display area of the flexible display device. A large display device can be implemented by connecting such flexible display devices with the reduced bezel with one another. For example, a large display device may be implemented by tiling multiple display devices.
In order to bend or fold the non-display area of a display device, it is necessary to make the lines disposed in the bending area robust against the bending stress. By increasing the width of the lines to withstand the bending stress, it is possible to suppress cracking or disconnection of the lines. And, in a high-resolution display device, the number of lines to be disposed in a given area of the non-display area is increased, such that the maximum width of the lines is limited.
Therefore, in order to dispose a plurality of lines in a given area of the non-display area, it is contemplated to reduce the width of lines for transmitting signals or reduce the spacing between the lines, for example. And, if the width of the lines is reduced, the resistance may increase such that a voltage drop may occur, whereby the luminance of the OLED device may become uneven. In addition, if the spacing between the transistors and the lines is reduced, short-circuit may be formed therebetween.
Under the circumstances, what is required is an OLED device capable of suppressing the above-described defects while achieving high definition.